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Objective: Impaired insight into illness in schizophrenia is associated with illness severity and deficits in premorbid intellectual function, executive function, and memory. A previous study of patients aged 60 years and older found that illness severity and premorbid intellectual function accounted for variance in insight impairment. As such, we aimed to test whether similar relationships would be observed in earlier life., Methods: A retrospective analysis was performed on 1 large sample of participants (n = 171) with a DSM-IV-TR diagnosis of schizophrenia aged 19 to 79 years acquired from 2 studies: (1) a psychosocial intervention trial for older persons with schizophrenia (June 2008 to May 2014) and (2) a diffusion tensor imaging and genetics study of psychosis across the life span (February 2007 to December 2013). We assessed insight into illness using the Positive and Negative Syndrome Scale (PANSS) item G12 and explored its relationship to illness severity (PANSS total modified), premorbid intellectual function (Wechsler Test of Adult Reading [WTAR]), and cognition., Results: Insight impairment was more severe in later life (≥ 60 years) than in earlier years (t = -3.75, P < .001). Across the whole sample, the variance of impaired insight was explained by PANSS total modified (Exp[B] = 1.070, P < .001) and WTAR scores (Exp[B] = 0.970, P = .028). Although age and cognition were correlated with impaired insight, they did not independently contribute to its variance. However, the relationships between impaired insight and illness severity and between impaired insight and cognition, particularly working memory, were stronger in later life than in earlier life., Conclusions: These results suggest an opportunity for intervention may exist with cognitive-enhancing neurostimulation or medications to improve insight into illness in schizophrenia across the life span., Trial Registration: Original study registered on ClinicalTrials.gov (identifier: NCT00832845)., (© Copyright 2017 Physicians Postgraduate Press, Inc.)

Objective: Although hyperprolactinemia carries a long-term risk of morbidity, the threshold of dopamine D2/3 receptor (D2/3R) occupancy for hyperprolactinemia has not been investigated in older patients with schizophrenia. Data were taken from a positron emission tomography (PET) study conducted between August 2007 and August 2015. The present post hoc study included 42 clinically stable outpatients with schizophrenia (DSM-IV) (mean ± SD age = 60.2 ± 6.7 years) taking olanzapine or risperidone. Subjects underwent [¹¹C]-raclopride PET scans to measure D2/3R occupancy before and after reducing their dose of antipsychotic by up to 40%. Blood samples were collected before each PET scan to measure prolactin levels., Methods: The relationship between prolactin levels and D2/3R occupancy was examined using stepwise linear regression analyses. The D2/3R occupancy thresholds for hyperprolactinemia were explored using Fisher exact tests., Results: Prolactin levels decreased following dose reduction (mean ± SD = 24.1 ± 30.2 ng/mL to 17.2 ± 15.1 ng/mL; P < .001). Prolactin levels were associated with female gender (β = .32, P = .006, vs male), antipsychotics (β = .23, P = .02, risperidone vs olanzapine), and D2/3R occupancy (β = .23, P = .04). Those with D2/3R occupancy of 66% or higher were more likely to have hyperprolactinemia than those with D2/3R occupancy lower than 66% (P = .03). Sensitivity, specificity, positive predictive value, and negative predictive value of this threshold were 0.44, 0.81, 0.78, and 0.48, respectively. We identified a D2/3R occupancy threshold for hyperprolactinemia of 66% in older patients with schizophrenia, which is lower than that reported in younger patients (73%) by other researchers., Conclusions: Our results suggest a higher sensitivity to antipsychotics in older patients. Prolactin levels could assist in the determination of appropriate antipsychotic dosing to minimize adverse effects., Trial Registration: ClinicalTrials.gov identifier: NCT00716755., (© Copyright 2016 Physicians Postgraduate Press, Inc.)

Objective: Antipsychotic polypharmacy (APP) is employed routinely, although it remains controversial because robust evidence supporting its efficacy is lacking. In addition, it is associated with increased costs, higher antipsychotic dosing, and greater risk of side effects. Surprisingly, no prospective, randomized, double-blind studies have addressed this issue; the present investigation set out to fill this gap in knowledge., Method: A 12-week, double-blind, randomized, placebo-controlled, single-site study was carried out in individuals with schizophrenia or schizoaffective disorder (DSM-IV) receiving a designated primary antipsychotic plus a secondary antipsychotic, with doses stabilized for each. Individuals were randomly assigned to APP (N = 17), reflecting current treatment, or antipsychotic monotherapy (APM) (N = 18), in which the secondary antipsychotic was discontinued. Assessments occurred weekly during month 1 and every 2 weeks during months 2 and 3; the primary outcome measure was the Brief Psychiatric Rating Scale (BPRS) total score. Other measures included the Clinical Global Impressions (CGI) scale, Simpson-Angus Scale, and Barnes Akathisia Scale. The study was carried out between August 2006 and March 2011., Results: Withdrawal due to clinical deterioration occurred in 1 individual receiving APP (5.8%) and in 4 individuals in the APM group (22.2%). Overall, however, there was no indication of clinical worsening with APM, as measured using BPRS and CGI scale., Conclusions: Almost 80% (n = 14) of individuals with schizophrenia or schizoaffective disorder currently receiving APP could be safely transitioned to APM with no clinical deterioration. For those who do deteriorate, risk appears greatest in the first several months. From another perspective, results also indicate that a minority of individuals benefit from APP, and research focusing on identifying this group may represent the best strategy to curb excessive use of APP., Trial Registration: ClinicalTrials.gov identifier: NCT00493233., (© Copyright 2016 Physicians Postgraduate Press, Inc.)

Objective: The primary objective of this article is to review the literature regarding clinical effects, pharmacokinetics, and pharmacodynamics of antipsychotics in older people and to examine potential mechanisms underlying the age-related antipsychotic sensitivity., Data Sources: Data for this review were identified by searches of PubMed (1950-2007) and references from relevant articles and books. Search terms included antipsychotic, neuroleptic, elderly, aging, pharmacokinetics, pharmacodynamics, and dopamine, and only articles written in English or Japanese were consulted., Data Selection: Studies, reviews, and books pertaining to the clinical effects, pharmacokinetics, and pharmacodynamics with regard to the use of antipsychotics in older patients were selected., Data Synthesis: The prevailing practices and clinical guidelines suggest that elderly patients can obtain therapeutic benefits at a lower dose and experience adverse effects from antipsychotics more often than younger patients, although there are still few trials that have directly compared elderly patients with the young. The literature suggests an age-related increase in brain access of drugs and demonstrates a decrease with age in the principal components in the dopaminergic system, including endogenous dopamine level and dopamine receptor density., Conclusions: While clinicians conclusively hold that patients become more sensitive to antipsychotics as they become older, this proposition has only modest empirical support and warrants further investigation. Age-related functional decline in the dopaminergic system predicts lower antipsychotic doses for older patients. We propose a hierarchical series of testable hypotheses to address the relative contribution of age-related pharmacokinetic and pharmacodynamic changes to antipsychotic drug sensitivity., (©Copyright 2009 Physicians Postgraduate Press, Inc.)

Objective: Long-acting risperidone administered intramuscularly biweekly is approved for the management of schizophrenia. However, dosing of long-acting antipsychotics is frequently extended in clinical practice, and a recent clinical trial has lent support to monthly dosing of long-acting risperidone. The objective of this positron emission tomography (PET) study was to examine the striatal dopamine D(2) binding of long-acting risperidone administered intramuscularly once a month., Method: Following at least 3 maintenance monthly injections of 50 mg long-acting risper-idone, 7 patients with a DSM-IV diagnosis of schizophrenia or schizoaffective disorder under-went PET using [(11)C]raclopride to measure D(2) binding potential within 4 days of the next scheduled injection. Data were collected from May to October 2003. This PET study was part of a larger 52-week clinical study wherein individuals received long-acting risperidone once monthly over a 1-year interval. One-year follow-up data were obtained from the 52-week parent investigation., Results: The mean +/- SD D(2) receptor occupancy was 56% +/- 24% (range, 29%-82%). Of note, there were 4 subjects with less than 60% D(2) occupancy, none of whom relapsed over the course of the 1-year follow-up. The mean +/- SD total plasma level of risperidone plus 9-hydroxyrisperidone was 16.6 +/- 12.3 ng/mL (range, 5.7-40.8)., Conclusion: As with plasma levels, there was considerable variability in D(2) occupancy levels for individuals receiving long-acting risperidone. This work suggests a possibility that sustained D(2) occupancy at or above the accepted threshold with acute clinical response may not be necessary to maintain response, a hypothesis with important clinical implications as we consider antipsychotic dosing and future antipsychotic development., Trial Registration: clinicaltrials.gov Identifier: NCT00236353.

Objective: The pharmacokinetic and pharmacodynamic profile of the immediate-release (IR) formulation of quetiapine is characterized by a rapid peak in plasma level and striatal dopamine D(2) receptor occupancy, followed by a rapid decrease to baseline levels, necessitating the use of twice-daily dosing. An extended-release (XR) formulation of quetiapine is currently being developed to achieve similar efficacy using a once-daily dosing regimen. We compared the central D(2) receptor binding between the IR and XR formulations., Method: In this open-label, crossover positron emission tomography study using [(11)C]-raclopride, we compared the central D(2) receptor binding potential at expected peak and trough plasma levels using equivalent daily doses of the IR and XR formulations (300, 600, and 800 mg/day) in 12 subjects. Data were collected from April 2002 to May 2003., Results: The mean plasma level of quetiapine at trough was significantly lower than that at peak for all dose groups of both formulations except for IR 300 and 800 mg (all p values < .05), while the mean plasma level did not differ significantly between formulations at trough and peak. The mean occupancy at peak was significantly higher than that at trough for all dose groups other than IR 800 mg/day (all p values < .05) and did not differ significantly between formulations at trough and peak., Conclusion: Once-daily dosing of the XR formulation gives peak and trough plasma levels and central D(2) receptor occupancy comparable to twice-daily dosing of the IR formulation. These data should be considered while determining equivalent doses, as well as switching strategies.